So far, I have interacted with three penisses and three vaginas belonging to people at various points of the gender spectrum. A not-serious, probably very TMI, and potentially offensive summary of my observations can be found below the cut.
Regarding manual interaction, all three penisses responded largely to similar types of stimulation: the classical jerk-off. There was some interindividual variation in the preferred movement speed (P1 and P2 fast, P3 slow) and pressure (individually different, and different at different locations along the shaft and glans). In P2, the preferred areas to be stimulated usually included testicles, in P3, this was only the case at one sampled date. Only P2 was circumcised: exhibited drastically reduced glans sensitivity (necessitating more stimulation of other areas) and required lube (to avoid dry friction over the glans), whereas the intact foreskin of P1 and P3 allowed stimulation over the foreskin, facilitated only by their own fluids.
Fellatio was performed on P2 and P3. Preferred stimulation varied: P2 responded best to deep envelopment (including deepthroating) and fast movements combined with manual stimulation of the parts of the shaft outside the mouth, while P3 favored focusing on the glans with only occasional deeper stimulation and no manual interference (static holds for additional stability only). P2 liked intense suction and licking/sucking of the testicles; P3 required less intensity for suction and did not care much for attention to the testicles. Both responded well to long, thorough licks from the base of the shaft towards the tip.
Much of the variance may be explained by the vastly reduced sensitivity of P2’s glans due to the circumcision; however, this remains an unsupported assumption due to the small sample size.
The established preferences for movement speed remained consistent over all forms of stimulation, including intercourse. All penisses reached orgasm fairly reliably, with both inter- and intrapersonal variation in duration.
Types of preferred stimulation across vaginas was vastly more varied than across penisses, with none of them responding well to the porn-typical “bean flick” and only V2 preferring the second classical form of stimulation (vaginal thrusting). V1 responded best to gentle vertical or circular rubbing motions between the labia (preferably with additional lube), V3 to indirect clitoral stimulation through rhytmical, deep pressure downward or diagonally downward and sideways on the clitoral hood.
Oral stimulation was given only to V2, rendering comparisons impossible.
Regarding intercourse, V2 enjoyed vaginal thrusting and vibrations (as with manual stimulation). V3 occasionally enjoyed vaginal penetration, with a focus on stretching and eliciting sensations of fullness rather than movement or friction, while attempted penetration was unpleasant at other times. V1 was not sampled.
V2 reliably reached orgasm via vaginal thrusting, even multiple times in succession. V3 reached orgasm exclusively by its preferred clitoral stimulation, with or without additional penetration. V1 never orgasmed (reportedly even in self-stimulation).
Study limitations and conclusion
The sample sizes are very small and presumably not representative. Contact to penisses was on average much more frequent and extensive than to vaginas, both due to personal and external factors. All penisses belonged to people with testosterone-dominant bodies, while the vaginas were more varied (V3 was sampled throughout transitioning from an estrogen-dominant to a testosterone-dominant body, V2 belonged to a body extremely low in both). Due to these limits of the present study, any conclusion drawn is necessarily preliminary and only weakly supported.
The narrower range of possible stimulation methods in penisses (discounting more exotic practices like sounding or CBT, which would require verbal negotiation in any case) is both benefit and drawback: on the one hand, less variation means less possibility to explore new pathways to pleasure, on the other, it virtually guarantees success for anyone wanting to pleasure a partner with a penis. Additionally, the highly responsive built-in feedback system offers an easy start for beginners: noticing twitches and/or further swelling is simple even without conscious attention and correlate well with experienced pleasure.
Vaginas offer a wider range of opportunities to explore and be fascinated by human differences, but also a wider range of opportunities to fail and be frustrated. Physical feedback is largely delayed and hard to notice: increasing wetness may be difficult to distinguish from the baseline (which varies with hormonal fluctuations) and easily escape attention in vaginas who prefer stimulation not focused on the vaginal opening itself, labial or clitoral swelling might be very subtle, and both indicators are poorly correlated with subjectively experienced arousal.
These factors could be compensated by verbal feedback and/or instructions, or possibly placing more weight on non-genital indicators of arousal (non-verbal sounds of appreciation, body language, facial expressions). However, many people are uneasy with communicating their sexual needs and desires, especially if the needed explanation would be quite lengthy and/or detailed. While most seem to be capable of and comfortable with single-word instructions like “faster”, such are only useful if their partner already found a good method of stimulation and the desired adjustment is small. If e.g. said partner is focused on the vaginal opening when clitoral stimulation is wanted, or applying pressure in a completely wrong direction, single-word instructions and comments fail.
This is unfortunate for the passive partner, who is left unsatisfied, and the active partner, who can only try to guess what might give their partner pleasure and could very well fail despite best intentions and even past experience, potentially resulting in frustration, shame, and embarrassment.
In conclusion, I prefer penisses so far, but am open to further experimentation with partners willing and able to communicate their wishes clearly. (It’s much more fun that way.)